because it does take a great amount of energy to get to space.even operating in Low Earth Orbit, you have to maintain a constant velocity, there is still drag on the vehicles (gravity) that needs to be over come.

either way you still have to lift a certain amount of mass to a certain altitude, against gravity, against the resistance of the atmosphere, etc. and with Chemical rockets (or any system in the foreseeable future), that takes a great deal of energy. at this point there is no way around that.